1. Field of the Invention
This invention relates to fuse.
2. Description of the Related Art
A motor vehicle which is a moving body includes a large number of power transmission lines for transmitting power itself and various signals, such as bas bars in electric connection boxes (junction block, relay box, fuse block, etc.), terminals for connectors for electric connection.
The main tendency of the voltage of the power transmitted along the power transmission line is 14 V for a general passenger car, and 28 V (14xc3x972) for a large scale vehicle such as a bus or truck (both in terms of an effective voltage). However, particularly for the passenger car, it has been proposed to adopt a power system for supplying an electric power with a higher voltage value than before in view of demands of improvement in driving efficiency of loads and driving with at an optimum efficiency for each load.
The above power transmission line includes fuse blocks from which a large number of fuses can be removed in order to protect electric circuits for various electric appliances (since the fuse block may have a relay or bus bar, it is referred to as a relay box or junction block, or generally referred to as xe2x80x9celectric connection boxxe2x80x9d. In this specification, the above fuse block, relay box, junction block are generally referred to as xe2x80x9celectric connection block.
The fuse which has been conventionally used for the electric connection block is such a fuse 51 as shown in FIG. 6. The fuse 51 includes a pair of terminals 52 arranged in parallel, a housing 54 which houses one ends 53 of these terminals 52 and a fusible body 55 which is formed integrally to the pair of terminals 52 and connect them to each other.
When the fuse 51 is mounted in the electric connection box, the terminals 52 are electrically connected to receiving terminals of the box, respectively. One of the receiving terminals is supplied with an electric power whereas the other thereof is electrically connected to various loads. Thus, the one of the terminal 52 is supplied with the electric power through the receiving terminal whereas the other thereof is connected to the loads. The terminals 52 are housed within the housing 54 in a state where their inner faces 61 are opposite to each other.
The housing 54 is made of insulating synthetic resin. The housing 54 is formed in a box shape. The interior of the housing 54 constitutes a housing chamber within which the one ends of the above pair of terminals 52 are housed.
As shown in FIGS. 6 and 7, the fusible body 55 connects the one ends 53 of the terminals 52 to each other. The fusible body 55 is coupled at its both ends with the inner faces 61 which are located at the one ends 53 of the terminals 52. The fusible body 55 includes a fusing portion 62 which fuses when the current value of the electric power supplied from the one of the terminals 52 exceeds a prescribed current value. The fusible portion 62 is formed to have a small sectional are a of the fusible body 55.
Where the fuse 51 thus configured is mounted on the electric connecting box, when the current value of the electric power supplied from the one of the terminals 52 through the one receiving terminal exceeds the prescribed current value, the fusing portion 62 of the fusible portion 55 fuses to stop supply of the electric power to the load.
In the fuse 51 shown in FIG. 6, since the fusible 55 is coupled with the opposite inner faces of the terminals 52, there is a relatively small space 60 (FIGS. 6 and 8) in which the fused potion 62 of the fusible body 55 formed between the inner faces 61 within the housing chamber can scatter. Further, it is generally known that the fusing portion 62 of the fusible body 55 scatters higher momentum as the current value in fusing increases.
In the above conventional fuse 51, when the fusing potion 62 of the fusible body 55 fuses with a higher current value than before, it scatters with higher momentum. The fused fusible body 55 might short-circuits the terminals to each other within the space 60.
This means difficulty of assuring the insulation between the terminals 52. In this case, supply of the electric power to the load which should be stopped may continue, and therefore the electric power with an excessive current value may be supplied to the load.
An object of this invention is to provide a fuse which can surely stop supply of an electric power to a load when the electric power with the current which exceeds a current value of fusing a fusible body is supplied.
In order to attain the above object, in accordance with this invention, there is provided a fuse including a pair of terminals arranged in parallel, a housing having a housing chamber for housing respective one ends thereof and a fusible body for coupling the pair of terminals with each other, wherein the fusible body is connected to respective end faces of the one ends of the pair of terminals.
In this configuration, since the fusible body is connected to the respective end faces of the one ends of the pair of terminals, the fusible body can be lengthened, and the distance between the connecting positions at the pair of terminals can be increased. For this reason, the fused fusible body is difficult to remain the pair of terminals. Therefore, after the fusible body has fused, the fuse surely prevents the pair of the terminals from being communicated with each other. Thus, when the power with a current value which exceeds the fusing current value of the fusible body is supplied, supply of the power to the load can be surely stopped.
Preferably, the housing comprises a first inner wall which is opposite to the respective end faces of the pair of terminals and constitutes the housing chamber, and
the pair of terminals are arranged in a state where the end faces of their one ends are apart from the inner wall.
In this configuration, since the above end faces are apart from the first inner wall, the space where the fusible body can scatter in the housing chamber can be increased. Therefore, deposition of the fused fusible body on the surfaces of the terminals can be suppressed so that the fused fusible body is difficult to remain the pair of terminals. Accordingly, after the fusible body has fused, the same effect as described above can be obtained.
Preferably, the housing the housing further comprises:
a second inner wall opposite to the first inner wall;
a first partition wall which extends from the first inner wall toward the the second inner wall and is located between the plurality of terminals in a direction they are arranged in parallel; and
a plurality of second partition walls which extend from the second inner wall toward the first inner wall and are located between the first partition wall and the pair of terminals, respectively.
In this configuration, since the first partition wall and second partition walls are located between the pair of terminals, the fused fusible body is more difficult to remain the pair of terminals. Accordingly, after the fusible body has fused, the same effect as described above can be obtained.
Preferably, the fusible body is bent to include
a pair of first extending segments which extend from the pair of terminals in a direction leaving therefrom, respectively;
a pair of second extending segments which extend from ends of the first extending segments in a direction the pair of terminals approach each other;
a pair of third extending segments which extend from ends of the second extending elements in a direction approaching the pair of terminals; and
a coupling segment which couples the pair of third extending segments.
In this configuration, since the fusible body is bent to include the first to the third extending segment and coupling segment, the fusible body can be lengthened. Therefore, the fused fusible body is more difficult to remain the pair of terminals. Accordingly, after the fusible body has fused, the same effect as described above can be obtained.
Preferably, the first pair of and third pair of extending segments are formed along the first partition wall, and the second pair of extending segments and the coupling segment are formed along the first inner wall. In this configuration, since the fused fusible body is apt to be deposited on the first and second partition walls and the first inner wall, the fused fusible body is more difficult to remain the pair of terminals. Accordingly, after the fusible body has fused, the same effect as described above can be obtained.